1. Field of the Invention
The invention relates to a telecommunication system, for example an Internet Protocol (IP) telecommunication system, and to equipment units for use in the system.
It relates more particularly to a telecommunication system in which some terminals form groups and one terminal in each group can send all the other terminals messages such as IP packets that must not be understandable by the terminals in the other groups.
2. Description of the Prior Art
To be sure of solving this problem, the messages are usually encrypted. To this end, algorithms and keys are negotiated between the terminals two by two. In other words, a secure message can be sent to only one addressee and not to a plurality of addressees simultaneously. This being so, if a group comprises n terminals, each message must be sent n−1 times.
This proliferation of secure messages to be sent increases the traffic and can saturate the network. Furthermore, the sessions that set up secure links between the terminals two by two can also increase the traffic.
The invention eliminates these drawbacks.